You might want to check the wildlife laws in the area you caught the fish. What you did might be highly illegal and you could be fined or even jailed, depending on your age. I know that where I used to live, you couldn't even walk in some areas because of the wildlife there, you couldn't hunt a type of animal, and you couldn't hurt or remove anything that animal ate.

Hey you all I live in trinidad! and no they are not protected..oh and in case you all did know i am a wild life enthusiast..i have saved many many snakes...and other wildlife from becoming road kill and from being masacared by hurtfull people...this is a baby mullet guys adult get to 18 inches...would you all rather have seen him dead? and heard he was going to be my dinnner ?? because here people dont care they eat just about any si2e they can get ! so just be happy he is getting expensive care and proper treatment..he is 4 inches and in a 75 gal tank..hows that? what more can he ask for? fresh shrimp every day...hmmm he has life in london! so...im no newbie when it comes to fish care! i have many many fish and other pets so im well aware of the needs and behaviour of my animals..so i will say again appreciate the comments whether you like it or not :)..because im happy he is mines and is getting the best of care !

I don't think fish laws in Trinidad are very strict MissPokemaster. If it's a popular game/food fish, then I don't think it'd be endangered either..
This fish also has it better than many wild caught animals because he wasn't forced into some lengthy shipping to get to a fish store or whatever..
I used to keep minnows over the summer, I'd always let them go in the fall so they could do whatever minnows do in the winter, lmao.

I used to have sun fish that were in canals and kept them in my 120 gallon aquarium. Better than what would happen to them when the canal dried out! As long as the fish is well taken care of, and not an endangered species, I don't see what the problem is.